The present invention relates to the terminal structure of a connector. More specifically, the invention relates to the terminal structure of a connector for electrically connecting a contact connected to a print substrate with a connecting pin connected to an external terminal. More specifically, the invention relates to the above terminal structure without requiring the use of caulking, soldering, or the like.
Referring to FIGS. 14 to 16, pair of terminal structures is shown, each having a connector of this kind. Each terminal structure is conventionally constructed of a housing 1, a spring pin 4 and a contact 5. The housing 1 is in the shape of a box. The spring pin 4 is inserted into a through hole 1a formed in a central position of the housing 1. The spring pin 4 engages the through hole 1a. The contact 5 is fixed by caulking or crimping to a convex portion on the bottom face of the spring pin 4.
The housing 1 is constructed of a basic portion 6 and an upper stage portion 8. The basic portion 6 is located on the lower side of the housing 1 and supports a caulking portion 3 of the spring pin 4. The upper stage portion 8 is located on the upper side of the basic portion 6 and supports the upper portion of the spring pin 4.
The above spring pin 4 is inserted into the housing 1 from the bottom side of the bottom portion 2 of the basic portion 6. The spring pin 4 is engaged with the basic portion 6 in such a way that the upper portion of the spring pin 4 is projected from the top of the upper stage portion 8.
The spring pin 4 is constructed of a sleeve portion 10, a sliding terminal 11, and a spring 11a. The sleeve portion 10 is in an elongated cylindrical shape, having a diameter that permits inserting the sleeve portion 10 into the through hole 1a of the housing 1. The spring 11a is contained in the sleeve portion 10.
The sleeve portion 10 has an elongated cylindrical shape with an opening in its upper portion. The sleeve portion 10 has a caulking portion 3, an air hole 10a, and a flange portion 10b. The caulking portion 3 is formed at the lower end of the sleeve portion 10. The caulking portion 3 has a diameter smaller than that of the sleeve portion 10. The air hole 10a is formed in the lower side portion of the sleeve portion 10. The flange portion 10b is located in an intermediate position of the sleeve portion 10, projecting onto a circular circumference along an outside diameter of the sleeve portion 10.
The sliding terminal 11 includes a contact portion 12 and an engaging portion 12a. The contact portion 12 has a cylindrical portion with a diameter smaller than that of the sleeve portion 10 to permit the cylindrical portion to fit within the sleeve portion 10. The outer end of the contact portion 12 is semi-spherical. The engaging portion 12a has a diameter larger than that of the contact portion 12 and slightly smaller than that of the inside diameter of the sleeve portion 10. The bottom face of the engaging portion 12a is a contact face, contacting the spring 11a. The bottom face of the engaging portion 12a is also useful as an electric connection.
When a spring pin 4 having such a structure is assembled, the spring 11a is first inserted into the sleeve portion 10. The engaging portion 12a of the sliding terminal 11 is then inserted into the open portion of the sleeve portion 10. In this state, the engaging portion 12a slightly resists the biasing force of the spring 11a. While maintaining this state, the top of the sleeve portion 10 is crimped to a diameter smaller than the engaging portion 12a and slightly larger than the diameter of the contact portion 12. This maintains the engaging portion 12a inside the sleeve portion 10. In the spring pin 4 assembled in this way, the sliding terminal 11 is slidably moved in a longitudinal direction of the sleeve portion 10, thereby permitting it to be projected and recessed. When the sliding terminal 11 is depressed, the air within the sleeve portion 10 is discharged from the air hole 10a. When the sliding terminal 11 moves outward, air is drawn into the air hole 10a and into the sleeve portion 10. Accordingly, the spring pin 4 has a structure that permits smooth motion of the sliding terminal 11.
The contact 5 is formed in an elongated plate shape of a predetermined width, with a bend 14 at an intermediate position. A through hole 5a is formed in one end portion 13 of the contact 5. The through hole 5a has a diameter that permits inserting the caulking portion 3 therethrough, before the caulking is performed. A connecting end portion 17 is formed in another end portion 16 of the contact 5 by bending its free end in a curve.
When the housing 1, the spring pin 4 and the contact 5 are assembled, the sliding terminal 11 is first directed upward and inserted into the through hole 1a of the housing 1 from the bottom side. The flange portion 10b is press-fitted into the inner wall face of the through hole 1a to engage the inner wall face of the sleeve portion 10. Caulking portion 3 is not caulked or crimped at this time.
The caulking portion 3 is fitted into the through hole 5a of the contact 5. The contact 5 is fixed in place by crimping the projecting end of the caulking portion 3 onto the outer surface of the contact 5 around the through hole 5a. At this time, the bend 14 in the contact 5 is supported between supporting pieces 15 formed in the bottom portion 2 of the housing 1. The bend 14, supported by the supporting pieces 15 and the caulking portion 3, is held so that a force exerted on the other bent end portion 16 at the outer end of the contact 5 resiliently deflects the outer end of the contact 5.
However, in the terminal structure of the connector of the prior art explained above, the contact 5 is engaged with the lower end of the spring pin 4 and the caulking portion 3 by caulking. Therefore, there is a technical restriction on the size of the caulking portion 3 and the contact 5. Hence, there is a limit in the assembly of the structure of the connector. For example, there is insufficient contact area in the connector of the prior art when an attempt is made to adapt the structure to connectors having contacts in millimeter sizes.